The best way I’ve found to introduce letter and number formation for my preschool-age boys is salt trays. I trace the number the way I want them to form it, using a rhyme to help them remember, and then they copy it. My 4 year old really wanted to make his own “3” and after he traced the one I made a few times, I let him. The chants for numbers 1-3 (courtesy of ABC Jesus Loves Me): 1: “Straight down and then you’re done. That’s the way to make a one.” 2: “Around and back on the railroad track.” 3: “Around the tree. Around the tree. That’s the way to make a three.”